Accurate Response Selection and Inhibition in Healthy Aging: An Event-Related Potential Study

Inhibitory control is thought to be critical for appropriate response selection in an ever-changing environment and to decline with age. However, experimental paradigms (e.g., go/no-go) confound stimulus frequency with demands to respond or inhibit responding. The present study eliminated that confound by using a modified go/no-go task controlling for stimulus frequency differences (using frequent-go, infrequent-go, and infrequent no-go types of stimuli) in healthy older and young adults. Event-related potential (ERP) components related to detection of response conflict (N2) and response evaluation (P3) were also examined. Behaviorally, older and young adults were sensitive to stimulus frequencies indicated by significant slowing for the infrequent-go compared with the frequent-go stimuli observed in both groups. Furthermore, older adults were characterized by reduced commission errors and overall slowing, suggesting that they could take advantage of their slower performance. Increase of N2 amplitude was evident for correctly inhibited no-go stimuli in both groups. In contrast, no-go stimulus-related increase in P3 amplitude could be observed only in the young. Stimulus frequency-related ERP amplitude differences were not significant either in the young or in the older adults. These results suggest preserved behavioral control over inappropriate responses in older adults and indicate that efficient response inhibition is related to compensatory mechanisms. The age-related decrease in the P3 amplitude suggests that the evaluation of response inhibition (a) could be independent of the detection of response conflict and (b) supports the notion of strategic differences in performance with age.